A number of mathematical models have been developed on the basis of some physiological experiments to describe neuronal activities. The Hudgkin-Huxley model was proposed to simulate the potential behavior of cell membranes, based on equivalent circuit principles and the results of experiments with the giant axons of gun squid [1]}. Its simplified versions including, Leaky Integrate-and-Fire neuron models, Izhikevich neuron models, and the adaptive exponential integrate-and-fire neuron model (aEIF) have been widely investigated [2]}, [3]}, [4]}, [5]}. In particular, the aEIF model has an exponential spiking mechanism combined with an adaptation [5]}. Protachevicz et al. verified that there exist spike and burst synchronization in different cortical areas in a random network of aEIF neurons [7]}. Based on the aEIF model, Borges et al. verified that bursting synchronization was more robust than spiking synchronization [8]}. More recently, in random networks of aEIF neural system, cluster synchronization induced by time delay has also been studied [9]}.
